Just bought a 1997 S420, hard code locked into 2nd gear. (OBDII code 1747, so it might be oil in the connector plug)
I'd like to clear the codes and see if I can drive it home in some gear other than 2nd, but I'm not willing to pay the dealer $122 for the attempt.

Is there any way of manually clearing the codes from the transmission computer without SDS, HHT, or similar?

Something simple, like shorting pin 1 to pin 10 for ten seconds?

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'79 300SD W116
'86 190E 2.3-16V W201
'92 300D 2.5 W124
'99 E320 4MATIC S210

I have heard of doing it on the diagnostic plug under the hood.Just shorting a pin to ground. Sometimes disconnecting battery will reset some faults.Also check the computer box under the hood,next to firewall.If soaked with fluid clean area,I use brake cleaner,but electrical contact cleaner is best.Let dry,and see if that helps for awhile,then order a plug.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Never heard of battery disconnection doing anything for hard fault codes.
I have a connector and an ignition coil coming in the mail today, then I'm going to go to where the car is, try to get cylinder #8 to start firing, unplug #8 injector if I can't, and drive it 40 miles home. Would actually be a couple of miles shorter and 20 minutes quicker if I can get it up to freeway speed, but I have no desire to scream down the freeway for 30 miles at 55mph in 2nd gear. 3rd gear maybe, but not 2nd.
I'm not really able to do much in the seller's driveway, but I did get permission to yank the #8 spark plug. The electrical connector at the right front of the tranny, and any oil wicking to the TCU, will have to wait for tomorrow.

__________________
'79 300SD W116
'86 190E 2.3-16V W201
'92 300D 2.5 W124
'99 E320 4MATIC S210

Oh, well. Replacing #8 plug and coil got rid of the rough running, but I couldn't find the 38 pin data connector at the right rear of the engine compartment and it was starting to rain, so I didn't get to try any games with pin 10.

So I just drove it 42 miles home in 2nd gear. 45mph at 3550 rpm and 90-95°C on the water temp.

__________________
'79 300SD W116
'86 190E 2.3-16V W201
'92 300D 2.5 W124
'99 E320 4MATIC S210

Here are your options.... How to clean the ecu... No other way?

1998 E320 Transmission is KILLING me!! - Mercedes-Benz Forum

all the best,

MArtin

What is the description of the code?

From what I've read of these transmissions if a fault occurs during operation, the trans will limp into 2nd. However if what ever caused the fault is no longer there it will resume shifting at the next key cycle.

Apparently you still have a failed part.